Trimethylolpropane ester-based plasticizer composition for polyvinyl chloride resin

ABSTRACT

The present invention relates to a trimethylolpropane ester-based plasticizer composition for polyvinyl chloride resin, more particularly a plasticizer composition comprising trimethylolpropane ester capable of using as plasticizer of polyvinyl chloride resin. The present invention can prepare polyvinyl chloride resin having superior tensile strength, elongation, migration, and sheet heating loss etc. by using the plasticizer composition.

BACKGROUND OF THE INVENTION

[0001] (a) Field of the Invention

[0002] The present invention relates to a trimethylolpropane ester-basedplasticizer composition, and more particularly to a trimethylolpropaneester-based plasticizer composition used as a plasticizer when preparingpolyvinyl chloride resin.

[0003] (b) Description of the Related Art

[0004] Polyvinyl chloride (PVC) is a general resin that can attainvarious physical processing properties by suitably mixing additives suchas stabilizers, fillers, pigments, and plasticizers. Polyvinyl chloridewith the various physical processing properties is widely used as amaterial for goods such as wallpaper, gloves, and toys, as well as forpipe, electric wire insulation, and artificial leather. The plasticizeris an essential additive for preparation of polyvinyl chloride resin, toimpart various physical properties such as processability, flexibility,electric insulating ability, etc.

[0005] The representative plasticizers used in processing of polyvinylchloride resin include phthalate-based plasticizers, adipate-basedplasticizers, and trimellitate-based plasticizers, etc. The mostgenerally used plasticizer, di-2-ethylhexylphthalate (DEHP), isphthalate-based, and it plays a role as a standard plasticizer forperformance evaluation of other plasticizers.

[0006] On the other hand, trimethylolpropane ester is mainly awell-miscible lubricant for refrigerants, (U.S. Pat. No. 5,470,497), andit is also used as an additive for lubricating oil in automobile engines(U.S. Pat. No. 4,061,581). Furthermore, trimethylolpropane ester caneffectively remove precipitation materials from metal surfaces in engineparts of automobiles (Japanese Patent Laid-open Publication No. Heisei5093191 A2), and an ester prepared by synthesis of trimethylolpropaneand fatty acids improves friction resistance of a road surface withoutreduction of friction resistance of a wet road (Japanese PatentLaid-open Publication No. Heisei 1113444 A2).

[0007] Although the trimethylolpropane ester is used as an additive forlubrication as mentioned above, it has structurally weak physicalproperties compared with phthalate-based and trimellitate-basedplasticizers widely used in the related art, and thus it is not used asa plasticizer when processing polyvinyl chloride.

[0008] For example, as a plasticizer used in processing of polyvinylchloride resin, trimethylolpropane ester comprises mono-component esterseach synthesized by adding hexane or 2-ethylhexanoic acid as an acid ofan aliphatic group series, or benzoic acid as an acid of an aromaticgroup series, to trimethylolpropane as a triply-charged alcohol.

[0009] In addition, triethanolmethane ester is a plasticizer havingphysical properties superior to trimethylolpropane ester or otherplasticizers. The trimethylolpropane ester was inferior in physicalproperties, as mentioned, as the ester of the mono component has toomany weak bonds to play a role as a plasticizer, even in the case whencompatibility with polyvinyl chloride resin does not exist (U.S. Pat.No. 3,939,201).

SUMMARY OF THE INVENTION

[0010] It is an object of the present invention to provide atrimethylolpropane ester-based multi-component synthesized plasticizercomposition by adding benzoic acid as an aromatic acid and aliphaticmono-carboxylic acid with 3 to 10 saturated linear or branched carbonatoms to trimethylolpropane as a triply-charged alcohol so that apolyvinyl chloride resin body having superior tensile strength,elongation, migration resistance, and sheet heating loss etc. can beprepared by using it as a plasticizer during polyvinyl chloride resinprocessing.

[0011] In order to achieve the object, the present invention provides aplasticizer composition comprising trimethylolpropane ester shown in thefollowing Formula 1:

[0012] wherein R₁, R₂, and R₃ are a phenyl group or an alkyl group with3 to 10 and preferably 4 to 5 carbon atoms, respectively.

[0013] Furthermore, the present invention provides a polyvinyl chlorideresin body comprising the plasticizer composition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention is described in detail as follows.

[0015] The mixture of trimethylolpropane (TMP) ester of the presentinvention comprises a) trimethylolpropane-tri-(2-ethyl hexanoate), b)benzoic acid 2,2-bis-(2-ethyl-hexanoyloxymethyl)-butyl ester, c)2-ethylhexanoic acid 2,2-bis-(benzoyloxymethyl)-butyl ester, and d)trimethylol propane-tri-benzoate. That is, the 4 different kinds ofester in the trimethylolpropane ester compound shown in the aboveFormula 1.

[0016] The trimethylolpropane ester plasticizer composition of thepresent invention, used in processing of polyvinyl chloride resin havingsuperior physical processing properties such as compatibility, migrationresistance, etc., is prepared by adding benzoic acid and 2-ethylhexanoicacid as raw materials to trimethylolpropane.

[0017] The mixture comprises 5 to 60 wt % oftrimethylolpropane-tri-(2-ethyl hexanoate), 20 to 70 wt % of benzoicacid 2,2-bis-(2-ethyl-hexanoyloxymethyl)-butyl ester, 5 to 50 wt % of2-ethylhexanoic acid 2,2-bis-(benzoyloxymethyl)-butyl ester, and 1 to 30wt % of trimethylol propane-tri-benzoate; and more preferably comprises15 to 40 wt % of trimethylolpropane-tri-(2-ethyl hexanoate), 4.0 to 50wt % of benzoic acid 2,2-bis-(2-ethyl-hexanoyloxymethyl)-butyl ester, 15to 35 wt % of 2-ethylhexanoic acid 2,2-bis-(benzoyloxymethyl)-butylester, and 1 to 10 wt % of trimethylol propane-tri-benzoate.

[0018] When the mixture of trimethylolpropane ester of the presentinvention is processed with polyvinyl chloride, the physical propertiesthereof are at least equal to physical properties of the prior art, andparticularly sheet volatile loss and migration resistance are superiorwhen compared with DEHP used as a standard plasticizer.

[0019] Trimethanolpropane ester of mono-component no multi-component,for example in the case of ester synthesized by adding only lauric acidas an aliphatic acid with 12 carbon atoms to trimethylolpropane, isdifficult to use as a plasticizer due to its non-compatibility withpolyvinyl chloride. In the case of ester synthesized is by adding only2-ethylhexanoic acid to trimethylolpropane, it has compatibility, butmigration resistance is poor and flowing out the processed sheet surfaceis problematic.

[0020] On the other hand, in the case of a multi-componenttrimethylolpropane ester, different physical properties are showndepending on kinds of alcohol and carboxylic acid used. That is, amulti-component ester synthesized by using trimethylolpropane and lauricacid and 2-ethylhexanoic acids as raw materials is not compatible withpolyvinyl chloride resin, in the same way as a case of adding onlylauric acid to trimethylolpropane for synthesis. If the estersynthesizes by simultaneously adding 2-ethylhexanoic acid and aceticacid to trimethylolpropane, 24 hrs after the specimen production flowingthe plasticizer out of the specimen becomes problematic, sincecompatibility is superior but migration resistance falls.

[0021] As mentioned, with both multi-component trimethylolpropane esterand mono-component trimethanolpropane ester, selective synthesis of acidand alcohol is very important because it is hard to produce all thedesired physical properties such as compatibility, migration resistanceetc. with polyvinyl chloride resin.

[0022] Furthermore, in the case of migration resistance, generally thereis an effect on the structure of ester materials or the outsideenvironment. A plasticizer having a high molecular weight has excellentmigration resistance of more than a plasticizer having a low molecularweight among the structure of ester materials.

[0023] Therefore, the multi-component trimethylolpropane ester mixtureaccording to the present invention prepares a suitable composition asaforementioned, by adding suitable acids and alcohol as raw materials,namely 2-ethylhexanoic acid-as the aliphatic acid and benzoic acid asthe aromatic acid, to trimethylolpropane.

[0024] The plasticizer composition comprising trimethylolpropane esterof the present invention is prepared by the following method.

[0025] In concrete terms, in order to prepare a plasticizer compositioncomprising trimethylolpropane ester comprising a) 5 to 60 wt % oftrimethylolpropane tri 2-ethylhexanoate, b) 20 to 70 wt % of benzoicacid 2,2-bis 2-ehtylhexanoyloxymethyl butyl ester, c) 5 to 50 wt % of2-ethylhexanoic acid 2,2-bis benzoyloxymethyl butyl ester, and d) 1 to30 wt % of trimethylpropane tribenzoate, i) 10 to 30 wt % oftrimethylolpropane, ii) 20 to 70 wt % of 2-ethylhexanoic acid, iii) 10to 60 wt % of benzoic acid, iv) 1 to 10 wt % of xylene, and v) 0.05 to 1wt % of tetraisopropyltitanate are added to a flask equipped with astirrer and condenser, the mixture is reacted for 4 to 20 hrs at 220°C., and un-reacted acid is removed through decompressing with a vacuumpump. The reactant is neutralized with 5 to 15 wt % of sodium hydroxideand washed, and then adsorbent is added to the reactant to remove waterby hydrating under vacuum, followed by filtering.

[0026] In the process, xylene is an entrainer, andtetraisopropyltitanate plays the part of a catalyst.

[0027] The present invention provides a polyvinyl chloride resin bodyhaving excellent tensile strength, elongation, migration resistance, andsheet heating loss etc. using the trimethylolpropane ester compositionas a plasticizer.

[0028] Hereinafter, the present invention is described in more detailthrough the following EXAMPLES and COMPARATIVE EXAMPLES. However, thefollowing EXAMPLES are only for the understanding of the presentinvention, and the present invention is not limited to the followingEXAMPLES.

EXAMPLES Example 1

[0029] (Preparation of Plasticizer Composition ComprisingTrimethyloipropane Ester)

[0030] To a 2 l, 4-neck round flask equipped with a stirrer and acondenser, 268.36 g of trimethylolpropane, 576.84 g of 2-ethylhexanoicacid, 366.39 g of benzoic acid, 50 g of xylene as an entrainer material,and 2.83 g of tetraisopropyltitanate as a catalyst were added, and thereaction was performed for 10 hrs by raising the temperature of themixture to 220° C.

[0031] After reaction, un-reacted acid was removed by evacuating theflask to 2 mmHg with a vacuum pump at 200° C., and the flask contentswere neutralized with 5 wt % of sodium hydroxide and a washing anddrying process was performed, and then the trimethylolpropane estermixture was obtained by adding absorbent to the resultant and filtering.

[0032] The composition ratio was 18.21 wt % of trimethylolpropanetri-2-ethylhaxate, 42.82 wt % of benzoic acid 2,2-bis2-ethylhexanoyloxymethyl butyl ester, 31.23 wt % of 2-ethylhexanoic acid2,2-bis benzoyloxymehtyl butyl ester, 6.49 wt % of trimethylolpropanetribenzoate, and 1.25 wt % of other components.

[0033] (Method for Processing of Polyvinyl Chloride)

[0034] In order to measure physical properties of the trimethylolpropaneester mixture obtained, the specimen was prepared to ASTM D638 standard.That is, 60 phr of the obtained trimethylolpropane ester plasticizermixture, 3 phr of calcium-zinc stabilizer (LTX-620S, product of KOREADAEHYUP CHEMICAL CO., LTD), and 0.2 phr of stearic acid was mixed withpolyvinyl chloride resin (LS100, product of LG. CHEMICAL CO., LTD), anda 5 mm sheet was prepared with a working roll mill over 3 min at 165° C.Thereafter a press operation was performed preheating for 3 min, heatingfor 3 min, and cooling for 3 min at 185° C., and then a 1 mm sheet wasfabricated to prepare a plurality of dumbbell-shaped type C samples.

[0035] (Experiment of Physical Properties)

[0036] The specimen prepared by the method was pulled cross head speedby 500 mm/min through the ASTM D638 method (That is, U.T.M as a testinstrument), and then tensile strength and elongation was measured at aplace on cutting the specimen. Tensile strength (kgf/mm²) was calculatedas load value(kgf)/thickness(mm)×width(mm), and elongation(%) wascalculated as extension/initial length×100.

[0037] Needle of hardness experimental instrument (C type) was got downperfectly, and then the hardness value was read shown after 10 sec. Thehardness was measured by the average value testing at 5 positions foreach specimen.

[0038] Sheet heating loss was calculated by measuring initial weight(Wi) to the forth decimal place for each specimen, and then fixing thespecimens in an oven at 130° C. using a clamp. Thereafter the specimenwas stored for 4 hrs or more in thermostat by taking out after 3 hrs,and the specimen weights (Wo) were measured, and then sheet heating losswas calculated by Equation 1 below. $\begin{matrix}{{H\quad e\quad a\quad t\quad i\quad n\quad g\quad l\quad o\quad s\quad s} = {\frac{\left( {{W\quad i} - {W\quad o}} \right)}{W\quad i} \times 100}} & \left\lbrack {{Equation}\quad 1} \right\rbrack\end{matrix}$

[0039] Migration resistance was calculated by measuring initialweight(Wi) to the forth decimal place for each specimen, and eachspecimen sheet (3 cm×3 cm) was placed between polystyrene (PS) plates inan oven at 80° C. and left for 48 hrs under a pressure of 1 kg.Thereafter the specimen was stored for 4 hrs or more in thermostat bytaking out at oven, and the specimen weights (Wo) were measured, andmigration resistance was calculated by Equation 2 below. $\begin{matrix}{{M\quad i\quad g\quad r\quad a\quad t\quad i\quad o\quad n\quad r\quad a\quad t\quad e} = {\frac{\left( {{W\quad i} - {W\quad o}} \right)}{W\quad i} \times 100}} & \left\lbrack {{Equation}\quad 2} \right\rbrack\end{matrix}$

[0040] Static heat-resistance was measured using a Mathis oven. Aspecimen of 40 cm×2 cm was introduced into the oven at 195° C., it wasremoved in 30 mm increments at 3-minutes intervals, and appearancechanges such as color at each interval were evaluated based on DEHP usedas the standard plasticizer. Results of the physical properties measuredby the method are shown in Table 2.

Example 2

[0041] The trimethylolpropane ester and the specimen were prepared bythe same method as in Example 1, except that materials and amounts wereas shown in Table 1 below, and the results of physical propertymeasurements are shown in Table 2 below.

[0042] The composition ratio of the ester mixture was 25.65 wt % oftrimethylolpropane tri-2-ethylhaxanoate, 44.72 wt % of benzoic acid2,2-bis 2-ethylhexanoyloxymethyl butyl ester, 24.05 wt % of2-ethylhexanoic acid 2,2-bis benzoyloxymehtyl butyl ester, 3.47 wt % oftrimethylolpropane tribenzoate, and 2.11 wt % of other components.

Example 3

[0043] The trimethylolpropane ester and the specimen were prepared bythe same method as in Example 1, except that materials and amounts wereas shown in Table 1 below, and the results of physical propertymeasurements are shown in Table 2 below.

[0044] The composition ratio of the ester mixture was 34.51 wt % oftrimethylolpropane tri-2-ethylhaxanoate, 44.56 wt % of benzoic acid2,2-bis 2-ethylhexanoyloxymethyl butyl ester, 17.52 wt % of2-ethylhexanoic acid 2,2-bis benzoyloxymehtyl butyl ester, 1.38 wt % oftrimethylolpropane tribenzoate, and 2.03 wt % of other components.

Comparative Example 1

[0045] The trimethylolpropane ester and the specimen were prepared bythe same method as in Example 1, except that the most widely usedplasticizer, di-2-ethylhexylphtalate (DHEP, product of LG. CHEMICAL CO.,LTD) was used, and the measured physical property results are shown inTable 2.

Comparative Example 2

[0046] The trimethylolpropane tri-2-ethylhexanoate and the specimen wereprepared by the same method as in Example 1, except that materials andamounts were as shown in Table 1 below, and the results of physicalproperty measurements are shown in Table 2 below.

Comparative Example 3

[0047] The trimethylol propane-tri-laurate and the specimen wereprepared by the same method as in Example 1, except that materials andamounts were as shown in Table 1 below, and the results of physicalproperty measurements are shown in Table 2 below.

Comparative Example 4

[0048] The trimethylolpropane ester mixture and the specimen wereprepared by the same method as in Example 1, except that materials andamounts were as shown in Table 1 below, and the results of physicalproperty measurements are shown in Table 2 below.

Comparative Example 5

[0049] The trimethylolpropane ester mixture and the specimen wereprepared by the same method as in Example 1, except that materials andamounts were as shown in Table 1 below, and the results of physicalproperty measurements are shown in Table 2 below. TABLE 1 Example Com.Example Division (g(mole)) 1 2 3 2 3 4 5 Material of ester Trimethylol268.36 268.36 268.36 268.36 268.36 268.36 268.36 propane (2) (2) (2) (2)(2) (2) (2) 2-ethylhexa 576.84 663.37 721.05 951.80 — 634.50 — noic acid(4) (4.6) (5) (6.6) (4.4) Benzoic 366.39 293.09 244.26 — — — — acid (3)(2.4) (2) Lauric — — — — 1442.2 440.70 661.10 acid (7.2) (2.2) (3.3)Acetic — — — — — — 336.90 acid (3.3) Xylene 50 50 50 50 50 50 50Tetraisopropyl- 2.83 2.39 2.90 2.85 3.61 2.15 3.00 titanate

[0050] TABLE 2 Com. Com. Com. Com. Com. Example Example Example ExampleExample Example Example Example Division 1 2 3 1 2 3 4 5 Tensile 2.201.90 1.85 1.75 1.87 1.70 No No strength common common (kgf/mm²) propertyproperty Elongation 363 350 343 378 390 400 (%) Migration 2.32 3.15 3.613.95 5.12 6.53 resistance (%) Hardness 84 82 83 78 84 80 Sheet 2.25 2.572.78 7.24 4.45 4.26 heating loss (%) Static heat- equality equalityequality standard equality inferiority resistance

[0051] As can be seen in Tables 1 and 2, Examples 1 to 3 that weresynthesized using trimethylolpropane, 2-ethylhexanoic acid, and benzoicacid as raw materials were equal in static heat-resistance, and theyshowed superior physical properties in tensile strength, migrationresistance, and sheet heating loss etc. compared withdi-2-ethylhexylphthalate (Comparative Example 1) used in the standardplasticizer.

[0052] In addition, the mono-component ester synthesized by adding only2-ethylhexanoic acid to trimethylolpropane (Comparative Example 2) andthe mono-component ester synthesized by adding only lauric acid totrimethylolpropane (Comparative Example 3) had compatibility, but aproblem of bad migration resistance etc. occurred.

[0053] Furthermore, the ester synthesized by adding 2-ethylhexanoic acidand lauric acid with 12 carbon atoms as aliphatic acid totrimethylolpropane (Comparative Example 4) and the ester synthesized byadding lauric acid with 12 carbon atoms as aliphatic acid and aceticacid to trimethylolpropane (Comparative Example 5) were difficult to useas plasticizers due to lack of compatibility with polyvinyl chloride.

[0054] As can be seen in the experimental results, when multi-componentpolyvinyl chloride resin was processed, in the case of themulti-component trimethylolpropane ester mixture as a plasticizer,namely the ester synthesized as a composition of trimethylolpropane,2-ethylhexanoic acid, and benzoic acid, a polyvinyl resin body can beprepared having excellent physical properties.

[0055] The present invention can prepare polyvinyl chloride resin havingsuperior tensile strength, elongation, migration, and sheet heating lossetc. by using the plasticizer composition.

What is claimed is:
 1. A plasticizer composition comprisingtrimethylolpropane ester shown in the following Formula 1:

wherein R₁, R₂, and R₃ are a phenyl group or an alkyl group with 3 to 10and preferably 4 to 5 carbon atoms, respectively.
 2. The compositionaccording to claim 1, wherein the composition comprises: a)trimethylolpropane-tri-2-ethyl hexanoate; b) benzoic acid2,2-bis-(2-ethyl-hexanoyloxymethyl)-butyl ester; c) 2-ethyl hexanoicacid 2,2-bis-(benzoyloxymethyl)-butyl ester; and d)trimethylolpropane-tri-benzoate.
 3. The composition according to claim2, wherein the composition comprises: a) 5 to 60 wt % oftrimethylolpropane-tri-2-ethyl hexanoate; b) 20 to 70 wt % of benzoicacid 2,2-bis-(2-ethyl-hexanoyloxymethyl)-butyl ester; c) 5 to 50 wt % of2-ethyl hexanoic acid 2,2-bis-(benzoyloxymethyl)-butyl ester; and d) 1to 30 wt % of trimethylolpropane-tri-benzoate.
 4. The compositionaccording to claim 2, wherein the composition comprises: a) 15 to 40 wt% of trimethylolpropane-tri-2-ethyl hexanoate; b) 40 to 50 wt % ofbenzoic acid 2,2-bis-(2-ethyl-hexanoyloxymethyl)-butyl ester; c) 15 to35 wt % of 2-ethyl hexanoic acid 2,2-bis-(benzoyloxymethyl)-butyl ester;and d) 1 to 10 wt % of trimethylolpropane-tri-benzoate.
 5. Thecomposition according to claim 1, wherein the composition is prepared bya method comprising steps of reacting: i) 10 to 30 wt % oftrimethylolpropane; ii) 20 to 70 wt % of 2-ethylhexanoic acid; iii) 10to 60 wt % of benzoic acid; iv) 1 to 10 wt % of xylene; and v) 0.01 to 1wt % of tetraisopropyltitanate for 4 to 20 hrs. at 220° C.
 6. Thecomposition according to claim 1, wherein the composition is prepared bya method comprising steps of reacting: i) 5 to 25 wt % oftrimethylolpropane; ii) 35 to 65 wt % of 2-ethylhexanoic acid; iii) 10to 40 wt % of benzoic acid; iv) 2 to 7 wt % of xylene; and v) 0.01 to0.7 wt % of tetraisopropyltitanate for 4 to 20 hrs. at 220° C.
 7. Apolyvinyl chloride resin body comprising the composition according toclaim
 1. 8. A polyvinyl chloride resin body comprising the compositionaccording to claim
 2. 9. A polyvinyl chloride resin body comprising thecomposition according to claim 5.